At least 171 million people worldwide suffer from type II diabetes (NIDDM), which is characterized by hyperglycemia due to excessive hepatic glucose production and peripheral insulin resistance. Hyperglycemia is considered to be the major risk factor for the development of diabetic complications, and is likely to contribute directly to the impairment of insulin secretion seen in advanced NIDDM. Thus, consistent control of plasma glucose levels in NIDDM patients can offset the development of diabetic complications and beta cell failure seen in advanced disease. Plasma glucose is normally filtered in the kidney in the glomerulus and actively reabsorbed in the proximal tubule. SGLT2 appears to be the major transporter responsible for the reuptake of glucose at this site. A selective inhibitor of the sodium-dependent glucose transporter SGLT2 in the kidney is expected to normalize plasma glucose levels by enhancing the excretion of glucose in the urine, thereby improving insulin sensitivity, and delaying the development of diabetic complications.
The compound of the structure (I)
or pharmaceutically acceptable salts or solvates thereof (hereinafter dapagliflozin), an orally active SGLT2 inhibitor is disclosed in U.S. Pat. No. 6,515,117 (the disclosure of which is incorporated herein by reference in its entirety).
U.S. application Ser. No. 11/765,481 filed Jun. 28, 2007, published as US 2008-0004336 A1 discloses dapagliflozin in the form of its (S)-propylene glycol ((S)-PG) hydrate and its (R)-propylene glycol ((R)-PG) hydrate. The (S)-propylene glycol hydrate is referred to as form SC-3 and has the structure shown as (Ia).

The (R)-propylene glycol hydrate is referred to as form SD-3 and has the structure shown as (Ib).

Methods for preparing the (S)-PG hydrate and the (R)-PG hydrate of dapagliflozin are provided in U.S. application Ser. No. 11/765,481 filed Jun. 28, 2007, published as US 2008-0004336 A1 (the disclosure of which is incorporated herein by reference in its entirety).